The Media Creation Tool is a utility provided by Microsoft to directly upgrade the PC to latest version of Windows 10, or to create Windows 10 installation media in ISO file, USB flash drive or DVD disc. Users can use the Windows 10 installation media to install a new copy of Windows 10, perform a clean installation, or reinstall Windows 10.

The official Media Creation Tool is always available at the following URL, though you have to wait until the general availability of next major version of Windows 10, e.g. when Windows 10 v.1709 is officially released, to get the updated version:

The download link for Windows 10 Build 16299.15 Media Creation Tool (MCT) is officially released as below. Though both links still work and both downloads same build of MCT, but there are differences in size and other details, such as CPU architecture (leaked version appears to be 32-bit while official one 64-bit). But both should works properly and similarly.

However, you cannot simply run the Media Creation Tool version 16299.15 yet, as obviously Windows 10 Fall Creators Update is not yet released, and Media Creation Tool is not accessing the correct XML file that provides download information to the tool. If you attempt to run the Media Creation Tool 16299.15 now, you will get the following error:

Download the latest version A newer version of this tool is available. You must download and run the latest version to continue.